Process of making concrete



M O O Cross Reference E ami e COATINGOB PLASTICY' g I 9s Patented Apr. 18, 1933 "f tain u-ntity of soluble silicate as water lass I il1c1ou's sla 1n the concrete mixture 50 the insidf diict su rface "WRFanB le' silica.

*IIQUNII'I'IEDV STATES I roams, mcoaronarnn, OF NEW YORK, 11. Y., A. CORPORATION or NEW YORK IPROCESS OF MAKING CONCRETE No Drawing. H v V 8 a cable duct in which the corrosive effect of lime on the lead cable sheath is prevented or retarded.

Applicant discovered that certain substances tend to protect lead or lead alloy cable 10 sheath from corrosive attack and that this effect is due to the presence of the silicate ion that it is induced by solow aconcentratlon as 1s afiorded by asaturated calciu ilica te solution and that it is efi'ectlve within a relatively wlde range of hydrogen ion concentration.

Applicant further discovered that the corrosion of the lead cable sheath resulted in the formation of red crystalline lead monoxide which crystallizes from saturatedsolutions of lime or alkali plumbites or plumbates. The

alkali responsible for corrosion may be produced by a solution of lime or alkali salt, sodium chloridg or ordinary table sa lt wliichT's use 0 aw out street car switchesfin winter and occasionally finds its way into cable ducts where it is converted into caustic soda at the surface of the cable sheath as. a result of current flow from the earth to the sheath. This type of corrosion also occurs in newly manufactured concrete ducts owing to the presence of free lime in the concrete. Applicant further discovered that distilled vgater exposed to the air readily corro'd's cable sheath alloys and that this corrosive action may be prevented by the introduction of solid silicate or by the addition of finely divided s ca our.

' Kccofdi'ng to this invention concrete cable ducts are constructed by introducing a cereconstructmg te cable uc cate has the property of neutralizing and considerably retarding or preventing the corrosive lime effect on the cable sheath through the formation of a silicate film on the surface of the cable sheath. liable ducts after being constructed or laid may be impregnatg l Application filed March 16, 1929. Serial No. 3471737.

water; permeating through it or silicate ion content of not less than ha "of However, in the case when thesoluble silinonnnr m. Bonus or NEW YORK, 1v. Y., assrenon T0 BELL TELEPHONE LAIBO-BA- 7 cate is introduced in the concrete. mixture the I concrete should beof sucli composition that solution by contact with it should have satura' e so ution o c cium s1 i'cjat'e hydro gen ion con cut or not esst an 1 10" grams per liter of solution. What is claimed is V 1. The method of preventing the corrosion of lead alloy cable sheath enclosed in concrete ducts which consists in producing a saturated silicate condition adjacent the lead sheath which forms or causes to be formed a coating of an insoluble film omthe lead sheath. I

2. The method of preventing the corrosion of lead alloy cable sheath enclosed in concrete ducts which consists in, producing a saturated silicate condition adjacent the lead sheath forming a 

